RESUMO
Recently it has been shown that phosphorylation of the Ser8 residue in amyloid-beta (pS8-Abeta) is tightly involved in the pathogenesis ofAlzheimer's disease. Since this modification occurs in the key metal-binding domain of amyloid-beta, and thus should seriously affect the interaction of pS8-Abeta with zinc ions, this isoform might be a potential precursor of pathogenic oligomeric forms of amyloid beta. Hence the level of pS8-Abeta in human biological fluids (such as blood, urine, cerebral spinal fluid) might resemble the different stages of the pathogenesis of Alzhe- imer's disease. The aim of this workwas to develop a prototype of an analytical method for quantitative determination of the level of pS8-Abeta isoform in binary mixtures with native amyloid-beta in order to further use it to determine the levels of phosphorylated amyloid-beta in blood plasma samples of patients with Alzheimer's disease.